The present invention is generally directed to sterilization containers, and, more particularly, to a tamper-proof seal for providing an indication of whether the container has been opened subsequent to a sterilization process.
The sterilization of medical instruments is an important factor in preventing infection and the spread of disease. In this regard, specialized sterilization containers have been developed to facilitate sterilization and the storage of sterilized articles in such a manner that their sterilized state is maintained during storage. These containers generally permit entry of the sterilizing medium into the container during the sterilization process, but prevent the entry of airborne contaminants once closed.
In order to provide evidence that the contents of a container have been through a proper sterilization cycle, a removable or permanent tag, tape, label or other device is frequently provided on the exterior of the container. The label or other device may include an ink or other indicator which changes in appearance to demonstrate exposure to conditions sufficient to effect proper sterilization of the container contents. Thus, the intention of these devices is to provide assurances that, when the device on a container has changed in appearance, the container has gone through a proper sterilization cycle. This purpose is easily circumvented, however, simply by processing the device through a sterilization cycle prior to placing it on a container, giving the appearance that the entire container has been through the sterilization cycle.
Another deficiency in the use of these devices stems from the fact that, once the sterilization process has been completed, containers containing sterilized articles are frequently stored for relatively long periods of time before the articles are needed. During this storage period, there is a possibility that the container will be opened, causing contamination of the articles, and then subsequently reclosed. Such unauthorized opening of the container is not readily revealed by visual inspection, and could lead to the use of articles that are no longer sterile or that, perhaps, were never sterilized. Thus, while indicator devices potentially may show that a particular container has been subjected to a sterilization process sufficient to sterilize the articles contained therein, they cannot provide evidence as to whether the articles have become contaminated at any time subsequent to sterilization.
In order to provide evidence of the sterile integrity of the contents of these containers once a sterilization procedure has been completed, various devices have been developed which provide a visual indication that the container may have been opened. Typically, these devices include a seal which must be destroyed to unlock the locking mechanism which enables the container to be opened. Therefore, it can be assumed that, for any container having a broken or missing seal, the contents of the container are no longer sterile. Many of these devices, however, simply prevent the container from being opened, but provide no positive indication as to whether the container has been subjected to a complete sterilization process. Other devices may visually indicate that sterilization has taken place, but provide no region for inscribing data relative to the container and its contents. As a result, the use of these devices frequently requires additional elements to be used to record data relative to the container and/or to indicate that the container has been subjected to a sterilization process.
There therefore exists a need for a security device that enables the recordation of data relative to the contents of the container or other relevant data, that provides a reliable visual indication that the container has been subjected to a sterilization process, and that also reliably reveals whether the container has been opened subsequent to the sterilization process.
The present invention addresses these needs.
One aspect of the present invention provides a disposable seal for a container having a latch mechanism. In one embodiment, the seal includes a body and a tongue having one end connected to the body and a free end. The tongue includes a layer of a shrinkable material, preferably, a heat shrinkable material, such as a heat shrink vinyl.
In preferred embodiments, the body of the seal may include a sterilization indicator material. Such sterilization indicator material may consist of a sterilization indicating ink.
The free end of the tongue may initially be remote from the body, but be adhered to the body during use of the seal. An adhesive may be provided on the free end of the tongue to keep the tongue adhered to the body during sterilization.
The tongue may have an initial length and a length after sterilization which is less than the initial length. Desirably, the initial length of the tongue is sufficient to permit the tongue to be assembled in a use position to the latch mechanism of the container, but the length of the tongue after sterilization is not sufficient to permit such assembly.
In highly preferred embodiments hereof, the tongue may include at least one layer of a second material laminated to the shrinkable material. A layer of a third material also may be laminated to the shrinkable material so that the shrinkable material is disposed between the second and third materials. The second and third materials may be selected from the group consisting of polymers and, in particular, polyolefins. Moreover, the second and third materials may be the same. Where at least one layer of a second material is laminated to the shrinkable material, the tongue preferably has an initial thickness and a thickness after sterilization which is greater than the initial thickness.
Another embodiment of the seal in accordance with this aspect of the present invention consists of a body including a sterilization indicator material and a tongue having one end connected to the body and a free end. The sterilization indicator material may consist of a sterilization indicating ink. The tongue has an initial length and a length after sterilization which is less than the initial length.
Another aspect of the present invention provides a sterilization security system. The security system includes a sterilization container having a base and a lid matable with the base in sealing engagement. A latch mechanism on the container has a latched position for locking the lid to the base and an unlatched position for releasing the lid for removal from the base. A seal assembled to the latch mechanism obstructs the free movement of the latch mechanism from the latched position to the unlatched position. In one embodiment hereof, the seal has an initial thickness and a thickness after sterilization which is greater than the initial thickness. In another embodiment, the seal includes a body and a tongue having one end connected to the body and a free end, the tongue including a layer of a shrinkable material. The seals in accordance with these embodiments may have any of the features of the seals described above.
A further aspect of the present invention provides methods for safeguarding the sterility of a sterilization container having a base, a lid matable with the base in sealing engagement, and a latch mechanism having a latched position for locking the lid to the base and an unlatched position for releasing the lid for removal from the base. In accordance with the methods, articles to be sterilized are placed in the base and the lid is applied to close the base. The latch mechanism. may then be placed in the latched position to lock the lid to the base. Subsequently, a seal may be assembled. to the latch mechanism to obstruct the free movement of. the latch mechanism from the latched position to the unlatched position. In accordance with one method, the seal has a body including a sterilization indicator material and a tongue having at least one end connected to the body and a free end. As the container is processed through a sterilization treatment, the tongue shrinks to maintain the latch mechanism in the latched position, and a property of the sterilization indicator material changes to indicate completion of sterilization. After sterilization, the latch mechanism may be moved to the unlatched position to release the lid from the base, the movement of the latch mechanism from the latched position to the unlatched position breaking the tongue of the seal.
In another method, the seal has a body and a tongue having at least one end connected to the body and a free end. Upon processing the container through a sterilization treatment, the tongue increases in thickness to maintain the latch mechanism in the latched position. Moving the latch mechanism from the latched position to the unlatched position to release the lid from the base causes the tongue of the seal to break.